JP4774096B2 - Exhaust gas purification system for work machines - Google Patents

Description

  The present invention relates to an exhaust gas purification system for a work machine, and in particular, in a traveling work machine such as a hydraulic excavator, the particulate matter deposited on a filter for collecting the particulate matter contained in the exhaust gas is removed by combustion. The present invention also relates to an exhaust gas purification system for a work machine provided with a regenerator that regenerates a filter.

  As an exhaust gas purification system for purifying exhaust gas of a conventional diesel engine, for example, there are those described in Patent Document 1 and Patent Document 2. In an exhaust gas purification system described in Patent Document 1, a filter called a particulate filter (DPF: Diesel Particulate Filter) is disposed in an exhaust system of an engine in a transport vehicle such as a truck, and particles contained in the exhaust gas by this filter. The particulate matter (PM: Particulate Matter: hereinafter referred to as PM) is collected and the amount of PM discharged to the outside is reduced. In addition, in order to prevent clogging of the PM filter, the PM accumulation amount of the filter is determined by detecting the differential pressure across the filter, and when the PM accumulation amount exceeds the first threshold, the exhaust gas temperature is automatically increased. Automatic regeneration control that burns and removes PM accumulated on the filter, and regeneration by manual operation when the vehicle is stopped by turning on the warning lamp when the PM accumulation amount exceeds the second threshold value, which is larger than the first threshold value. When the start of the control is urged and the operator turns on the manual regeneration switch, manual regeneration control for increasing the temperature of the exhaust gas and burning and removing PM accumulated on the filter can be performed. The temperature of the exhaust gas is increased by oxidizing (burning) unburned HC by additional fuel injection in the expansion stroke after the main injection of the engine.

  The exhaust gas purification system described in Patent Document 2 regenerates a filter in a hydraulic working machine by applying a hydraulic load to the engine to increase the output of the engine to increase the exhaust gas temperature, burn filter deposits, and regenerate the filter. ing. Further, engine exhaust resistance is detected by a filter, and regeneration is automatically started when the exhaust resistance exceeds an allowable value (automatic regeneration control).

JP 2005-120895 A Japanese Patent No. 3073380

  The filter regeneration control in the exhaust gas purification system in a transport vehicle such as a truck includes automatic regeneration control performed during traveling and manual regeneration control performed while the vehicle body is stopped, as described in Patent Document 1. In the manual regeneration control, the PM accumulated on the filter is operated in a case where the PM continues to increase without being completely removed by the automatic regeneration control, and the PM is combusted and removed. That is, since the automatic regeneration control is performed while the vehicle is running, the PM accumulation amount of the filter due to the operation of the engine may be larger than the PM combustion removal amount due to regeneration. The amount of deposition will increase. In the manual regeneration control, PM accumulated in the filter is burned and removed reliably by stopping the vehicle body and raising the temperature of the exhaust gas by additional fuel injection or the like to burn and remove the PM accumulated on the filter.

  However, when the manual regeneration control technique is applied to a working machine such as a hydraulic excavator as described in Patent Document 2, there are the following problems.

  A work machine such as a hydraulic excavator is a machine that performs work by stopping a vehicle body. The operation is performed by driving a hydraulic pump with an engine and driving actuators such as a boom cylinder and an arm cylinder with the discharge oil of the hydraulic pump. Stopping the vehicle body and performing manual regeneration control with such a work machine means that the work must be stopped. However, since the threshold value (second threshold value) of the PM accumulation amount when starting the manual regeneration control is relatively large and the PM combustion removal amount is also relatively large, the regeneration time is relatively long. As a result, no work can be performed during regeneration, and work efficiency is significantly reduced.

  On the other hand, in the case of a working machine, taking an excavator as an example, when performing excavation and dumping work such as loading excavated earth and sand on a dump bed, it is not necessary to perform work such as waiting for dumping (working) Pause time). At this time, since the operation is suspended, the engine load is light and the exhaust gas temperature of the engine is relatively low. As a result, the effect of spontaneous combustion of PM deposited on the filter is reduced, and PM tends to accumulate in the filter.

An object of the present invention is to provide an exhaust gas purification system for a work machine that can efficiently burn particulate matter deposited on a filter by using a work downtime of the work machine and avoid a reduction in work efficiency. It is.

(1) In order to achieve the above object, the present invention is arranged in an exhaust system of a diesel engine, a filter for collecting particulate matter contained in exhaust gas, and burning particulate matter deposited on the filter And a regenerator for regenerating the filter. In the exhaust gas purification system for a work machine, setting means for presetting a work pause time of the work machine, means for informing that the work machine has entered a work pause state, And a regeneration control means for operating the regeneration device during the set work suspension time when it is notified that the work machine has entered the work suspension state, the regeneration control means comprising the filter The time required for burning and removing the accumulated particulate matter accumulated by the regenerator is calculated, and the work machine has entered the work pause state. Informed and the time that the calculation is assumed to start the operation of the reproducing device when longer than downtime was the setting.

In the present invention configured as described above, when the work machine enters the work pause state, the regenerating device is operated during a preset work pause time. Therefore, the particulate matter deposited on the filter using the work pause time is removed. Regeneration control for burning can be performed. Also, the operation downtime is the time during which particulate matter tends to accumulate in the filter. By using this time to burn the particulate matter deposited on the filter, the particulate matter deposited on the filter can be burned efficiently. Can be reduced. Further, by burning and reducing the particulate matter deposited on the filter during the operation downtime, an increase in the amount of particulate matter accumulated on the filter is suppressed, so that the frequency of request for manual regeneration control is reduced. Therefore, it is possible to prevent a reduction in work efficiency due to forced manual regeneration control during work.
In the present invention , the reproduction apparatus is operated using the work pause time set as described above to perform reproduction control. However, even if the amount of particulate matter accumulated in the filter is small, if the regeneration control is performed during the operation suspension time, the operation frequency of the regeneration device increases, and the fuel consumption of the engine may deteriorate.

  Therefore, the present invention is such that the operation of the playback device is started when the calculated time is longer than the set work pause time, and thus the calculated time even if it is notified that the work pause state has been entered. Is less than the set work pause time, the regenerating device does not operate, and it is possible to prevent the regenerating device from operating frequently and reducing the fuel consumption of the engine.

(2) In order to achieve the above object, the present invention provides a filter that is disposed in an exhaust system of a diesel engine and collects particulate matter contained in exhaust gas, and particulate matter deposited on the filter. In an exhaust gas purification system for a working machine comprising a regenerator that burns the filter and regenerates the filter, a setting means that presets a work pause time of the work machine, and notifies that the work machine has entered a work pause state And a regeneration control means for operating the regeneration device during the set work suspension time when it is notified that the work machine has entered the work suspension state, the regeneration control means, Calculate the amount of particulate matter accumulated in the filter and the amount of particulate matter that can be combusted by the regenerator at the set operation pause time. To those械starts the operation of the reproducing apparatus when the accumulation amount of the informed that entered the work pause state and the calculated particulate matter is larger than the deposition amount of the calculated combustible particulate matter To do .

As described in the above ( 1 ), the particulate matter deposited on the filter can be efficiently burned by using the work downtime of the work machine, and a reduction in work efficiency can be avoided. Is frequently operated, and the fuel consumption of the engine is prevented from being lowered.

( 3 ) In the above (1) or (2) , preferably, the means for notifying that the work machine has entered a work suspension state is operated by an operator when the work machine has entered a work suspension state. The first operating device.

As a result, regeneration control using the work suspension time (1) or (2) can be started at the operator's will.

( 4 ) In the above (1) or (2) , the work machine has an operation lever device operated at the time of work, and means for notifying that the work machine has entered a work suspension state is provided on the operation lever device. You may have a detection apparatus which detects an operation state, and the determination means which determines whether the said working machine entered into a work hibernation state based on the detection result of this detection apparatus.

As a result, when the work machine enters the work pause state, the regeneration control using the work pause time (1) or (2) can be automatically started without any operation by the operator.

( 5 ) In the above (1) or (2) , preferably, the setting means includes a second operating device that is operated by an operator of the work machine and inputs a work pause time of the work machine.

  Thereby, the operator can set the optimal work downtime according to the situation of the work site according to the operator's judgment.

( 6 ) In the above (1) or (2) , the work machine further includes an information storage device for storing operation data, and the setting means analyzes the operation data stored in the information storage device at predetermined time intervals. And you may have the analysis means which calculates the working stop time of the said working machine based on the analysis result.

  As a result, the work pause time can be set automatically.

  ADVANTAGE OF THE INVENTION According to this invention, the particulate matter deposited on the filter can be burned and reduced efficiently by using the work pause time of the work machine, and the reduction in work efficiency due to regeneration control can be avoided.

  Further, according to the present invention, it is possible to perform regeneration control using work pause time without reducing the fuel consumption of the engine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
<Overall configuration>
FIG. 1 is a diagram showing an exhaust gas purification system of a hydraulic excavator (work machine) according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a diesel engine (hereinafter simply referred to as an engine). The engine 1 includes an exhaust pipe 2 that exhausts exhaust gas to the outside, and a muffler 3 is connected to the tip of the exhaust pipe 2. The engine speed and torque of the engine 1 are controlled by the engine control device 4. As is well known, the engine control device 4 inputs a target rotational speed designated by the engine control dial, and an electronic governor provided in the engine 1 based on the target rotational speed and the actual rotational speed detected by the rotational speed detection sensor. And the number of revolutions and torque of the engine 1 are controlled by controlling the fuel injection amount.

  The engine control device 4 is connected to the vehicle body control device 21, the information storage device 22, the monitor control device 23, and the communication line 25 to form a vehicle body network.

  The vehicle body control device 21 inputs signals from a hydraulic system (described later) and sensors provided in the vehicle body, and performs arithmetic processing for hydraulic control and vehicle body control.

  The monitor control device 23 inputs detection signals from various sensors such as a fuel remaining amount sensor and a water temperature sensor (not shown) from the engine control device 4 and the vehicle body control device 21 via the communication line 25, and outputs the detection results to the display device 16. Performs display control for display. The monitor control device 23 controls setting input by the operation unit 17 provided in the display device 16.

  The information storage device 22 collects various signals input to the engine control device 4, the vehicle body control device 21, the monitor control device 23, etc. via the communication line 25 as operation data, and stores and stores them in a database in time series. To do. These data are periodically transmitted to the management server using a satellite communication terminal (not shown).

  The exhaust gas purification system according to the present embodiment is provided in a hydraulic excavator equipped with the above-described devices, and is disposed in the exhaust pipe 2 constituting the exhaust system of the engine 1 and is included in the exhaust gas. A filter device (DPF) 11 that collects the pressure, a differential pressure sensor 12 that detects a differential pressure across the upstream and downstream sides of the filter device 11 (pressure loss of the filter device 11), and a hydraulic excavator operated by an operator. A pressure sensor for detecting the presence or absence of operation of operation means related to work by detecting the presence or absence of a control pilot pressure of a work pause switch 13 (first operating device) and a remote control valve (described later) for notifying that a work pause state has been entered. 14, an electromagnetic switching valve 15 for applying a hydraulic load to the engine 1 at the time of regeneration control, and a function as an operation device (second operation device) for inputting work downtime An operation unit 17 of the display device 16 having the above vehicle body control unit 21, and a monitor controller 23 and the engine control unit 4. The filter device 11 includes a filter that collects particulate matter (PM) contained in the exhaust gas, and an oxidation catalyst that is disposed on the upstream side of the filter.

  The engine control device 4 receives a detection signal of the differential pressure sensor 12 and transmits the detection signal to the vehicle body control device 21 via the communication line 25. When the operation unit 17 is operated as an operation device for inputting the work suspension time, the monitor control device 23 inputs the work suspension time and transmits the work suspension time to the vehicle body control device 21 via the communication line 25. .

  When the vehicle body control device 21 receives the work suspension time from the monitor control device 23 via the communication line 25, it stores the work suspension time in a storage device such as a hard disk and sets it as a time for reproduction control. Further, the vehicle body control device 21 inputs the detection signal of the differential pressure sensor 12 transmitted from the engine control device 4, and also inputs the operation signal of the work suspension switch 13 and the detection signal of the pressure sensor 14, and outputs these signals. A predetermined calculation process is performed, and a regeneration start instruction signal and a regeneration stop instruction signal are output to the engine control device 4 via the communication line 25, and a control signal (ON control signal) is output to the electromagnetic switching valve 15. .

  The engine control device 4 includes a regeneration control unit 4a that functions as a regeneration device. When the engine control device 4 receives a regeneration start instruction signal from the vehicle body control device 21, the operation of the regeneration control unit 4a is started. When the reproduction stop instruction signal is received from 21, the operation of the reproduction control unit 4a is stopped. The regeneration control unit 4a performs regeneration control by controlling the electronic governor of the engine 1, and the vehicle body control device 21 outputs an ON control signal to the electromagnetic switching valve 15 to apply a load to the engine 1. As will be described later (for example, Patent Document 1), the engine speed is maintained at a predetermined speed (for example, 1750 rpm), and unburned HC is oxidized by post-injection (additional injection) in the expansion stroke after engine main injection. As a result, the temperature of the exhaust gas is raised, and the oxidation catalyst of the filter device 11 is activated by the high-temperature exhaust gas, whereby PM deposited on the filter is burned and removed.

  Further, the exhaust gas purification system has a manual regeneration start switch 18, and the vehicle body control device 21 inputs an operation signal of the manual regeneration start switch 18 to perform a predetermined calculation process, and communicates a regeneration start signal and a regeneration stop signal. While outputting to the engine control apparatus 4 via the line 25, a control signal is output to the electromagnetic switching valve 15. Also in this case, the engine control device 4 starts the operation of the regeneration control unit 4a when receiving the regeneration start signal, and stops the operation of the regeneration control unit 4a when receiving the regeneration stop signal.

In this specification, the regeneration control based on the operation signal of the work suspension switch 13 is referred to as suspension time utilization regeneration control, and the regeneration control based on the operation signal of the manual regeneration start switch 18 is referred to as manual regeneration control. In addition, the operation of the playback control unit 4a (playback device) is referred to as playback control as appropriate.
<Hydraulic system>
FIG. 2 is a diagram showing a hydraulic circuit device mounted on a hydraulic excavator that is a work machine according to the present embodiment. The hydraulic circuit device of the excavator includes a variable displacement main hydraulic pump 31 and a fixed displacement pilot pump 32 driven by the engine 1, a hydraulic motor 33 driven by pressure oil discharged from the hydraulic pump 31, and A plurality of hydraulic actuators including hydraulic cylinders 34 and 35, and a pilot operated flow control valve 37 that controls the flow (flow rate and direction) of pressure oil supplied from the hydraulic pump 31 to the hydraulic motor 33 and the hydraulic cylinders 34 and 35. Are connected to the downstream side of the pilot hydraulic power source 40, a pilot relief valve 41 that forms a pilot hydraulic power source 40, and maintains a constant pressure of the pressure oil discharged from the pilot pump 32. , ON / OF depending on the opening / closing status of the gate lock lever provided on the entrance side of the cab of the hydraulic excavator A control pilot pressure a connected to the controlled solenoid switching valve 43 and a pilot oil passage 44 on the downstream side of the solenoid switching valve 43 and operating the flow control valves 37 to 39 using the hydraulic pressure of the pilot hydraulic power source 40 as a source pressure. Remote control valves 45, 46 and 47 for generating .about.f, and a main relief valve 48 as a safety means for defining the upper limit of the discharge pressure of the main hydraulic pump 31. The remote control valves 45, 46, 47 are built in the left and right operation lever devices located on the left and right of the driver's seat in the cab.

  The primary ports of the remote control valves 45, 46, 47 are connected to the pilot oil passage 44, and the secondary ports are connected to the pilot lines 45a, 45b; 46a, 46b; 47a, 47b, and are generated by the remote control valves 45, 46, 47. The control pilot pressures a to f are guided to the pressure receiving portions of the flow control valves 37 to 39 through these pilot lines. A shuttle valve group 50 is connected to the pilot lines 45a, 45b; 46a, 46b; 47a, 47b. The shuttle valve group 50 includes shuttle valves 50a to 50f. The shuttle valve 50a is connected between the pilot lines 45a and 45b of the remote control valve 45, and the shuttle valve 50b is connected between the pilot lines 46a and 46b of the remote control valve 46. The valve 50c is connected between the pilot lines 47a and 47b of the remote control valve 47, the shuttle valve 50d is connected between the output ports of the shuttle valves 50a and 50b, and the shuttle valve 50e is connected between the output ports between the shuttle valves 50c and 50d. The shuttle valve 50f is connected between the output port of the shuttle valve 50e and the output port of the shuttle valve at the final stage related to the remote control valve of other operating means (not shown). As a result, the shuttle valve group 50 including the shuttle valves 50a to 50f extracts the maximum pilot pressure among the control pilot pressures a to f of the remote control valves 45 to 47 and the control pilot pressures of the remote control valves of other operating means (not shown). The shuttle valve 50f at the final stage of the valve group 50 outputs the maximum pressure. The pressure sensor 14 is connected to the output port of the shuttle valve 50f at the final stage, and detects the maximum pressure which is the output pressure of the shuttle valve 50f, thereby controlling the control pilot pressure of all the remote control valves including the remote control valves 45 to 47. Presence / absence, that is, presence / absence of operation of the operation means related to the work including the operation lever device of the remote control valves 45 to 47 is detected.

  A plurality of flow control valves including the flow control valves 37 to 39 are of a center bypass type, and these flow control valves are connected in series to a center bypass line 51 connected to a discharge oil passage of the hydraulic pump 31, and The downstream portion 51a is connected to the tank T. The electromagnetic switching valve 15 is connected to the most downstream portion 51 a of the center bypass line 51. The electromagnetic switching valve 15 is a two-position switching valve having an open position and a closed position. When there is no control signal (ON signal) from the vehicle body control device 21 and the solenoid is not excited, it is in the open position shown in the figure. When a control signal (ON signal) is output from the vehicle body control device 21 and the solenoid is excited, the position is switched from the open position to the closed position.

The electromagnetic switching valve 15 is switched to the closed position when the engine control device 4 operates the regeneration device (regeneration control unit 4a) (described later). When the electromagnetic switching valve 15 is switched to the closed position, the discharge pressure of the hydraulic pump 31 rises to the set pressure of the main relief valve 48, the load torque of the engine 1 that drives the hydraulic pump 31 increases, and the operation of the regeneration device Combined with (regeneration control), the exhaust gas temperature of the engine 1 can be raised.
<Hydraulic excavator>
FIG. 3 is a diagram illustrating an external appearance of a hydraulic excavator that is an example of a working machine including the hydraulic circuit device illustrated in FIG. 2. The hydraulic excavator includes a lower traveling body 100, an upper swing body 101, and a front work machine 102. The lower traveling body 100 has left and right crawler traveling devices 103a and 103b, and is driven by left and right traveling motors 104a and 104b. The upper swing body 101 is turnably mounted on the lower traveling body 100 by the swing motor 105, and the front work machine 102 is attached to the front portion of the upper swing body 101 so as to be able to be raised and lowered. The upper swing body 101 includes an engine room 106 and a cabin (operating room) 107. The engine 1 is arranged in the engine room 106. A gate lock lever is provided on the entrance side of the driver's seat in the cabin 107. An operation lever device incorporating remote control valves 35, 36, and 37 is disposed on the left and right. In addition, an engine control dial and a display device 16 are installed at appropriate positions in the cabin 107.

  The front work machine 102 has an articulated structure having a boom 111, an arm 112, and a bucket 113. The boom 111 rotates up and down by the expansion and contraction of the boom cylinder 114, and the arm 112 moves up and down and front and rear by the expansion and contraction of the arm cylinder 115. , And the bucket 113 is rotated up and down and back and forth by the expansion and contraction of the bucket cylinder 116.

In FIG. 2, the hydraulic motor 33 is, for example, a turning motor 105, the hydraulic cylinder 34 is, for example, an arm cylinder 115, and the hydraulic cylinder 35 is, for example, a boom cylinder 114. The hydraulic circuit device shown in FIG. 2 includes other hydraulic actuators and control valves corresponding to the travel motors 104a and 104b, the bucket cylinder 116, etc., but these are not shown in FIG.
<Processing content of regeneration control using work pause time of vehicle body control device 21>
FIG. 4 is a flowchart showing the processing contents of the work pause time use regeneration control of the vehicle body control device 21. The vehicle body control device 21 executes the arithmetic processing shown in FIG. 4 in a predetermined control cycle.

  First, the vehicle body control device 21 receives the detection signal of the differential pressure sensor 12 transmitted from the engine control device 4 and filters the differential pressure across the filter device 11 detected by the differential pressure sensor 12 (hereinafter referred to as DPF differential pressure). The amount of particulate matter currently deposited on the filter of the apparatus 11 (hereinafter referred to as PM deposition amount) is calculated, and the PM deposition amount is burned and removed by the regenerator from the calculated PM deposition amount. A required time (hereinafter referred to as a required playback time) is calculated (step S100).

  The PM accumulation amount is calculated by storing the relationship between the DPF differential pressure and the PM accumulation amount as shown in FIG. 5 in a memory table, and referring to the DPF differential pressure detected by the differential pressure sensor 12 in the table. This is done by determining the amount of PM deposited. In the memory table, as shown in FIG. 5, the relationship between the DPF differential pressure and the PM accumulation amount, in which the PM accumulation amount increases as the DPF differential pressure increases, is set. This relationship is obtained in advance by experiments and stored in the memory.

  The required regeneration time is calculated by storing the relationship between the PM accumulation amount and the regeneration necessary time as shown in FIG. 6 in a memory table, and referring to the calculated PM accumulation amount in the table to determine the corresponding regeneration required time. Do it by asking. In the memory table, as shown in FIG. 6, the relationship between the PM accumulation amount and the regeneration necessary time that the regeneration necessary time increases as the PM accumulation amount increases is set. This relationship is obtained in advance by experiments and stored in the memory.

  Next, it is determined whether or not the work stop switch 13 is operated by the operation signal of the work stop switch 13, that is, whether or not the work stop switch 13 is turned on (step S110), and the necessary regeneration time calculated in step S100 is monitored. It is determined whether or not the work suspension time input and set by the operation unit 17 of the control device 23 has been exceeded (step S120), the work suspension switch 13 is turned on, and the required regeneration time has exceeded the set work suspension time. The regeneration control start signal is output to the engine control device 4 (step S130), and the control signal (ON signal) is output to the electromagnetic switching valve 15 to switch the electromagnetic switching valve 15 to the closed position (step S140). As a result, the regeneration control is started with a hydraulic load applied to the engine 1.

  If the work pause switch 13 is not ON in step S110, or if the work pause time set in step S120 does not exceed the work pause time, the process returns to step S100, and the processes in steps S100 and S110 are repeated.

When the regeneration control is started by the processing of step S130 and step S140, it is then determined whether or not the work pause state is continued (step S150), and the time after the work pause switch 13 is turned on is described above. It is determined whether or not the set work pause time has been exceeded (step S160). Whether or not the work pause state is continued is determined by detecting the presence or absence of control pilot pressure of all remote control valves including the remote control valves 45 to 47 based on the detection signal of the pressure sensor 14. That is, when the absence of the control pilot pressure is detected, it is determined that the work pause state is continued, and when the presence of the control pilot pressure is detected, it is determined that the work is started. If the work pause state continues and the time after the work pause switch is ON does not exceed the set time, the process returns to step S130, and the processes of steps S130 to S160 are repeated.

If it is determined in step S150 that the work has started, or if the time after the work stop switch is turned on exceeds the set work stop time in step S160, a regeneration control stop signal is output to the engine control device 4 (step S150). S170), and the control signal output to the electromagnetic switching valve 15 is turned off to switch the electromagnetic switching valve 15 to the open position (step S180). As a result, the hydraulic load of the engine 1 is released and the regeneration control is stopped.
<Entering work downtime>
FIG. 7 is a diagram illustrating a configuration of the operation unit 17 of the display device 16 and a procedure for inputting work suspension time.

  The display device 16 includes a display panel 16a such as a liquid crystal, and the operation unit 17 includes a switch group including an F4 switch 17a to an F7 switch 17d and a menu switch 17e disposed below the display panel 16a.

On the display panel 16a of the display device 16, measurement values such as the hydraulic oil temperature, the radiator water temperature, and the engine fuel level are always displayed. When the menu switch 17e is pressed in this state, the screen is switched to the menu screen. The selection items on the menu screen include “DPF function”. In this menu screen, the F4 switch 17a and the F5 switch 17b function as up / down keys for moving the cursor (the shaded portion in the figure) displayed on the menu screen up / down, the F6 switch 17c as a determination key, and the F7 switch 17d as a return key. Function. When inputting the work pause time, the operator operates the F4 switch 17a and the F5 switch 17b (up / down key) to select “DPF function” and presses the F6 switch 17c (decision key) to decide. When the enter key 17c is pressed, the screen is switched to the DPF selection screen. The selection items on the DPF selection screen include “DPF regeneration interval setting”. In this screen, the operator operates the F4 switch 17a and the F5 switch 17b (up / down key) to select “DPF regeneration interval setting” and presses the F6 switch 17c (decision key) to decide. When the enter key 17c is pressed, the screen is switched to the DPF regeneration interval setting screen. On the DPF regeneration interval setting screen, a numerical value input screen of “body stop interval time” is displayed. In this screen, the F4 switch 17a and the F5 switch 17b function as + -keys for numerical input. The operator operates the + -keys 17a and 17b to input a numerical value of “body stop interval time” and presses the F6 switch 17c (decision key) to decide. By pressing the enter key 17c, the input numerical value is transmitted from the monitor control device 23 to the vehicle body control device 21 via the communication line 25 as a work pause time setting signal, and is set in the vehicle body control device 21.
<Processing content of manual regeneration control of vehicle body control device 21>
FIG. 8 is a flowchart showing the processing contents of the manual regeneration control of the vehicle body control device 21. The vehicle body control device 21 executes the arithmetic processing shown in FIG. 8 in a predetermined control cycle.

  First, the vehicle body control device 21 receives the detection signal of the differential pressure sensor 12 transmitted from the engine control device 4, and the differential pressure across the filter device 11 detected by the differential pressure sensor 12 is based on a preset regeneration start threshold ΔPUL. If the determination result is YES, a warning prompting the operator to start manual regeneration control is displayed on the display device 16 (step S210). If the determination result is NO, step S200 is performed. The process of S200 is repeated. Here, the regeneration start threshold value ΔPUL is a limit value for preventing the filter of the filter device 11 from being melted.

  When a warning prompting the start of manual regeneration control is displayed on the display device 16 in step S210, it is then determined whether or not the manual regeneration start switch 18 has been operated (ON) (step S220). If the determination result is YES, a regeneration control start signal is output to the engine control device 4 (step S230), and a control signal (ON signal) is output to the electromagnetic switching valve 15 to close the electromagnetic switching valve 15. The position is switched (step S240). As a result, the regeneration control of the engine control device 4 is started in a state where a hydraulic load is applied to the engine 1.

Next, it is determined whether or not the differential pressure across the filter device 11 detected by the differential pressure sensor 12 is smaller than a preset regeneration end threshold value ΔPDL (step S250). If the determination result is NO, the process is repeated to determine If the result is YES, a regeneration control stop signal is output to the engine control device 4 (step S260), and the control signal output to the electromagnetic switching valve 15 is turned OFF to switch the electromagnetic switching valve 15 to the open position (step S270). ). As a result, the hydraulic load on the engine 1 is released and the regeneration control of the engine control device 4 is stopped.
<Correspondence with Claims>
In the above, the operation unit 17 of the display device 16 when functioning as an operation device for inputting work suspension time constitutes setting means for presetting work suspension time of the work machine (hydraulic excavator), and the work suspension switch 13 is operated. A means for notifying that the machine (hydraulic excavator) has entered the work pause state is configured, and the processing function shown in FIG. 4 of the vehicle body control device 21 is performed when it is notified that the work machine has entered the work pause state. The regeneration control means for operating the regeneration device (reproduction control unit 4a) during the set work pause time is configured.

Further, in the present embodiment, the vehicle body control device 21 (regeneration control means) having the processing function shown in FIG. 4 is required for the regeneration device to burn and remove the current amount of particulate matter accumulated in the filter. The time is calculated, and the operation of the regenerator is started when it is known that the work machine has entered the work pause state and the calculated time is longer than the set work pause time.
<Operation>
Next, the operation of this embodiment will be described.

  In the case of a hydraulic excavator, when excavating and dumping work such as loading excavated earth and sand on a dump bed, there is always a time during which work such as waiting for dumping is not performed (work pause time). At this time, since the operation is suspended, the engine load is light and the exhaust gas temperature of the engine is relatively low. As a result, the effect of spontaneous combustion of PM deposited on the filter is reduced, and PM tends to accumulate in the filter.

  In the present embodiment, reproduction control is performed as follows using such work suspension time.

  First, since the dump waiting time varies depending on the work site, when working at a new work site, the operator estimates the dump waiting time suitable for the work site in advance and uses it for the regeneration control of the present invention from the dump waiting time. Determine and set possible work downtime. This setting is performed using the operation unit 16 as described above (FIG. 7).

  The operator then enters the actual work. In this operation, the dump bed becomes full of excavated earth and sand, and when the operator waits for the dump until the next empty dump arrives, the operator presses the work suspension switch 13. When the work stop switch 13 is pressed, the vehicle body control device 21 inputs the operation signal, and the time required for burning the current PM accumulation amount accumulated in the filter of the filter device 11 by the regeneration device (regeneration required time). ) Exceeds the set work pause time, a regeneration control start signal is output to the engine control device 4 (FIG. 4, steps S110 → S120 → S130), and a control signal is output to the electromagnetic switching valve 15 (FIG. 4, Step S140). As a result, filter regeneration control (combustion of PM accumulated in the filter) using the work excursion time of the excavator is started. On the other hand, even if the work suspension switch 13 is pressed, if the required regeneration time does not exceed the set work suspension time, the regeneration control is not started (FIG. 4, steps S120 → S100). When the set work pause time elapses after the start of the regeneration control, the regeneration control ends (steps S160 → S170 and S180).

  Also, once the regeneration control is started, if the next dump arrives earlier than planned and the work is to be resumed earlier than the set work pause time, the operator operates the operation lever device (remote control valve). The reproduction control is automatically stopped (steps S150 → S170 and S180), and the work can be started.

  On the other hand, although not shown, the engine control device 4 also has a function of automatic regeneration control, and performs a process of burning PM accumulated on the filter by automatic regeneration control during the operation of the hydraulic excavator. In this automatic regeneration control, for example, the pressure sensor 14 detects the differential pressure across the filter device 11 to determine the PM accumulation amount of the filter, and when the PM accumulation amount exceeds a threshold value, post injection in the expansion stroke after engine main injection is performed. (Additional injection) is performed, and the temperature of the exhaust gas is automatically raised to burn the PM deposited on the filter.

In addition, although the regeneration control and the automatic regeneration control using the work pause time are performed as described above, the PM accumulation amount of the filter increases, and the differential pressure across the filter device 11 becomes the regeneration start threshold value of the manual regeneration control. If ΔPUL is exceeded, a warning is displayed on the display device 16 (steps S200 → S210). When a warning is displayed on the display device 16, the operator stops the operation and operates the regeneration start switch 18 (ON). Thus, regeneration control is started in a state where a hydraulic load is applied to the engine 1 (FIG. 8, steps S220 → S240). Thereafter, when the differential pressure across the filter device 11 becomes smaller than the regeneration end threshold value ΔPDL, the manual regeneration control ends (steps S250 → S260 and S270).
<Effect>
As described above, according to the present embodiment, the following effects can be obtained.

  A hydraulic excavator is a machine that performs work by stopping a vehicle body. The operation is performed by driving the hydraulic pump 31 with the engine 1 and driving actuators such as the boom cylinder 114 and the arm cylinder 115 with the oil discharged from the hydraulic pump 31. When manual regeneration control is performed with such a hydraulic excavator, the operation must be stopped as described above. However, the regeneration start threshold value ΔPUL in the manual regeneration control is a limit value for preventing the filter of the filter device 11 from being melted, and the manual regeneration control time is relatively long. As a result, once manual regeneration control is started, no work can be performed during that time, so work efficiency is significantly reduced.

  In the present embodiment, as described above, the regeneration control is performed during the operation suspension time unique to the work machine such as a hydraulic excavator, and the PM deposited on the filter of the filter device 11 is burned. The working stop time of a working machine such as a hydraulic excavator is also a time during which PM is easily accumulated in the filter because the effect of spontaneous combustion of PM accumulated on the filter is reduced because the engine load is light. By performing regeneration control at a time when PM easily accumulates in the filter and burning and reducing the PM deposited on the filter, the particulate matter deposited on the filter can be efficiently burned and reduced. Since the increase in the amount of particulate matter accumulated on the filter is suppressed by burning and reducing the particulate matter deposited on the filter during the operation downtime, the frequency (number of times) of manual regeneration control is required. ) Is reduced, it is possible to prevent manual regeneration control from being forced during work, and to prevent work efficiency from being lowered.

  Further, when the regeneration device is operated during the operation stop time, if the regeneration control is performed even when the amount of PM accumulated in the filter of the filter device 11 is small, the operation frequency of the regeneration device increases and the fuel consumption deteriorates. there is a possibility. In the present embodiment, even if the work pause switch 13 is pressed, if the required work regeneration time does not exceed the set work suspension time, the regeneration control is not started, so that the fuel consumption is reduced due to frequent operation of the regeneration device. Can be avoided.

Furthermore, even if the regeneration control is once started, if the next dump arrives earlier than the set work pause time, the regeneration control automatically stops when the operator operates the operation lever device (remote control valve). Therefore, the work can be started freely without worrying about the state of the regeneration control.
<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a flowchart showing the processing contents of the vehicle body control device 21 in the present embodiment. The same steps as those shown in FIG. The difference from FIG. 4 is that steps S100A and S120A are provided instead of steps S100 and S120, and the operation of the regenerator is started by comparing the deposition amounts.

  That is, in this embodiment, in step S100A, the amount of particulate matter currently deposited on the filter of the filter device 11 from the differential pressure across the filter device 11 (hereinafter referred to as the DPF differential pressure) detected by the differential pressure sensor 12. (Hereinafter referred to as PM accumulation amount) is calculated, and the PM accumulation amount combustible in the set work pause time is calculated. This calculation can be easily performed using an inverse function of the relationship between the PM deposition amount and the regeneration necessary time as shown in FIG. In step S120A, instead of determining whether or not the required regeneration time exceeds the set work pause time, the current PM accumulation amount calculated in step S100A is burned at the set work pause time calculated in step S100A. It is determined whether or not a possible PM deposition amount is exceeded. If the determination is affirmative, a regeneration control start signal is output to the engine control device 4 (step S130), and a control signal (ON signal) is output to the electromagnetic switching valve 15 to close the electromagnetic switching valve 15. (Step S140), and the engine controller 4 regeneration control in a state where a hydraulic load is applied to the engine 1 is started.

In the present embodiment configured as described above, the same effect as that of the first embodiment can be obtained.
<Third Embodiment>
A third embodiment of the present invention will be described with reference to FIG. FIG. 10 is a flowchart showing the processing contents of the vehicle body control device 21 in the present embodiment, and the same steps as those shown in FIG. The difference from FIG. 4 is that step S110B is provided instead of step S110, and the detected value of the pressure sensor 14 is used to notify that the work machine has entered a work pause state.

That is, in the present embodiment, the work pause switch 13 is not provided, and in step S110B of FIG. 10, it is determined whether or not a predetermined time (for example, 1 minute) has elapsed after the work is stopped, and when the predetermined time has elapsed. It is determined that the operation has been suspended. Whether the operation is stopped is determined by inputting a detection signal of the pressure sensor 14 and detecting the presence / absence of control pilot pressures of all the remote control valves including the remote control valves 45 to 47 (whether the operation lever device is operated). . That is, when the absence of control pilot pressure is detected, it is determined that the work is stopped, and the elapsed time thereafter is counted.

Also in the present embodiment configured as described above, it is possible to notify that the excavator has entered a work suspension state, and the same effect as in the first embodiment can be obtained. Further, in this embodiment, when entering a dump waiting state, it is possible to automatically start the regeneration control using the work pause time without the operator having to operate the work pause switch. improves.
<Fourth embodiment>
A fourth embodiment of the present invention will be described with reference to FIGS. In this embodiment, instead of the operator inputting and setting the work pause time for regeneration control, it is calculated and set using the operation data stored in the information storage device.

  In FIG. 1, as described above, the information storage device 22 collects various signals input to the engine control device 4, the vehicle body control device 21, the monitor control device 23, and the like via the communication line 25 as operation data, Store and accumulate in the database in time series. The operation data to be collected includes detection data of the pressure sensor 14 input to the vehicle body control device 21.

  The vehicle body control device 21 calculates and sets the work suspension time for regeneration control using the operation data stored in the information storage device 22. FIG. 11 is a flowchart showing the processing contents of the vehicle body control device 21 at that time.

  In FIG. 11, the vehicle body control device 21 determines whether or not a predetermined time (for example, one day) has elapsed since the previous setting process (step S300), and when the predetermined time has elapsed, the information storage device 22 via the communication line 25. The operation data such as the detection data of the pressure sensor 14 relating to the work suspension time of the hydraulic excavator is acquired from the operation (step S310). Next, the operation data is analyzed to calculate the average value of the work pause time (step S320), and the average value is stored and set as the work pause time for regeneration control (step S330).

According to this embodiment, the same effect as that of the first embodiment can be obtained, and the operator can automatically calculate and set the reproduction control work pause time without inputting the operation time. Convenience is improved.
<Other variations>
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made within the spirit of the present invention. The modifications are listed below.

  1. In the above embodiment, fuel injection for regeneration control is performed by post-injection (additional injection) in the expansion stroke after engine main injection. However, a fuel injection device for regeneration control is provided in the exhaust pipe, and this fuel injection device The fuel injection for regeneration control may be performed by actuating.

  2. In the above embodiment, the control calculation for generating the regeneration start signal and the regeneration stop signal for the pause time utilization regeneration control and the manual regeneration control is performed by the vehicle body control device 21, but these control computations are performed by the engine control device 4. Also good.

  3. In the above embodiment, the PM accumulation amount of the filter is calculated using the DPF differential pressure detected by the differential pressure sensor 12. However, the state amount of the engine 1 may be detected and calculated. For example, a rotation sensor that detects the engine speed, a load sensor that detects the engine load, a temperature sensor that detects the exhaust gas temperature, and the like are provided, and these outputs are read to calculate the PM emission amount We and the PM combustion amount Wc, The PM accumulation amount of the filter can also be obtained by obtaining the PM accumulation amount Wa from Wa = We−Wc and adding the previous calculated value Wa1 to the PM accumulation amount Wa.

  4). In the first embodiment, when the work suspension switch 13 is operated, the regeneration required time is compared with the set work suspension time, and if the regeneration necessary time exceeds the set work suspension time, the work suspension time is exceeded. However, the value to be compared with the required regeneration time may not exactly match the set work pause time. For example, a value of about 20% before and after the set work pause time is set as a time to be compared with the required play time, and the playback control using the work pause time is started when the required play time exceeds the value. May be. This also makes it possible to reduce the frequency of regeneration control using the work pause time and prevent a reduction in fuel consumption, compared to a case where no restriction is provided. The same applies to the second embodiment, and the value to be compared with the amount of particulate matter currently accumulated in the filter is around the amount of particulate matter that can be combusted by the regenerator during the set operation downtime. A value of about 20% may be set, and regeneration control using work downtime may be started when the current amount of particulate matter accumulated in the filter exceeds that value.

5. In the above embodiment, the electromagnetic switching valve provided in the hydraulic circuit to apply a load for the exhaust gas temperature rise in the engine in the regeneration control, the hydraulic load on the engine by switching the electromagnetic switching valve in the closed position However, the engine may be loaded by other means. For example, it is possible to apply a load to the engine by providing a throttle valve in the exhaust pipe and restricting the flow path of the exhaust pipe with this throttle valve.

  6). In the above embodiment, the present invention is applied to a hydraulic excavator as a work machine. However, the present invention may be applied to a work machine other than the hydraulic excavator. Examples of work machines other than the hydraulic excavator include a wheel excavator and a crane truck. In this case as well, the same effects as those in the above embodiment can be obtained.

It is a figure which shows the exhaust-gas purification system of the hydraulic shovel (work machine) concerning one embodiment of this invention. It is a figure which shows the hydraulic circuit apparatus mounted in the hydraulic shovel which is a working machine. It is a figure which shows the external appearance of the hydraulic shovel provided with the hydraulic circuit apparatus shown in FIG. It is a flowchart which shows the processing content of work rest time utilization reproduction | regeneration control of a vehicle body control apparatus. It is a figure which shows the relationship between DPF differential pressure | voltage and PM deposition amount. The relationship between the amount of accumulated PM and the time required for regeneration It is a figure which shows the structure of the operation part of a display apparatus, and the input procedure of work stop time. It is a flowchart which shows the processing content of the manual regeneration control of a vehicle body control apparatus. It is a flowchart which shows the processing content of the vehicle body control apparatus in the 2nd Embodiment of this invention. It is a flowchart which shows the processing content of the vehicle body control apparatus in the 3rd Embodiment of this invention. It is a flowchart which shows the processing content when the vehicle body control apparatus in the 4th Embodiment of this invention calculates work stop time from driving | operation data.

Explanation of symbols

1 Engine 2 Exhaust pipe 3 Muffler 4 Engine control device 11 Filter device (DPF)
12 differential pressure sensor 13 work stop switch 14 pressure sensor 15 electromagnetic switching valve 16 display device 17 operation unit 18 manual regeneration start switch 21 vehicle body control device 22 information storage device 23 monitor control device 25 communication line 31 hydraulic pump 32 pilot pump 33 hydraulic motor 34, 35 Hydraulic cylinder 37-39 Flow control valve 40 Pilot hydraulic source 43 Electromagnetic switching valve 44 Pilot oil passage 45-47 Remote control valve 45a, 45b; 46a, 46b; 47a, 47b Pilot line 50 Shuttle valve group 50a-50f Shuttle valve 51 Center Bypass Line 100 Lower Traveling Body 101 Upper Revolving Body 105 Turning Motor 111 Boom 112 Arm 113 Bucket 114 Boom Cylinder 115 Arm Cylinder 116 Bucket Cylinder

Claims (6)

A working machine comprising a filter that is disposed in an exhaust system of a diesel engine and collects particulate matter contained in exhaust gas, and a regenerator that regenerates the filter by burning particulate matter deposited on the filter. In the exhaust gas purification system,
Setting means for presetting the work pause time of the work machine;
Means for notifying that the work machine has entered a work pause state;
A regeneration control means for operating the regeneration device during the set work suspension time when it is notified that the work machine has entered the work suspension state;
The regeneration control means calculates the time required for the regeneration device to burn and remove the current amount of particulate matter accumulated in the filter, and is informed that the work machine has entered the work pause state. An exhaust gas purification system for a working machine, wherein the operation of the regenerator is started when the calculated time is longer than the set work pause time. A working machine comprising a filter that is disposed in an exhaust system of a diesel engine and collects particulate matter contained in exhaust gas, and a regenerator that regenerates the filter by burning particulate matter deposited on the filter. In the exhaust gas purification system,
Setting means for presetting the work pause time of the work machine;
Means for notifying that the work machine has entered a work pause state;
A regeneration control means for operating the regeneration device during the set work suspension time when it is notified that the work machine has entered the work suspension state;
The regeneration control means calculates the accumulated amount of particulate matter accumulated in the filter and the accumulated amount of particulate matter combustible by the regeneration device at the set operation stop time, and the work machine is configured to perform the work. The operation of the regenerator is started when it is known that a dormant state has been entered and the calculated amount of accumulated particulate matter is greater than the calculated amount of combustible particulate matter deposited. Exhaust gas purification system for machines. The exhaust gas purification system for a work machine according to claim 1 or 2 ,
The means for notifying that the work machine has entered a work pause state is a first operating device operated by an operator when the work machine enters a work pause state. system. The exhaust gas purification system for a work machine according to claim 1 or 2 ,
The work machine has an operation lever device that is operated during work,
The means for notifying that the work machine has entered a work pause state includes a detection device that detects an operation state of the operation lever device, and whether the work machine has entered a work pause state based on a detection result of the detection device. An exhaust gas purification system for a work machine, comprising: a determination unit that determines The exhaust gas purification system for a work machine according to claim 1 or 2 ,
The exhaust gas purification system for a work machine, wherein the setting means includes a second operation device that is operated by an operator of the work machine and inputs a work pause time of the work machine. The exhaust gas purification system for a work machine according to claim 1 or 2 ,
The work machine further includes an information storage device for storing operation data,
The setting unit includes an analysis unit that analyzes operation data stored in the information storage device at a predetermined time interval and calculates a work pause time of the work machine based on the analysis result. Exhaust gas purification system.

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